Apparatus for implanting a preloaded localization wire

ABSTRACT

An apparatus for percutaneously implanting a localization wire into a tissue mass comprises a cannula with a preloaded localization wire having a distal end and at least one anchor. An actuator is in operable communication with the cannula and is configured for operation between a charged condition and a discharged condition to retract the cannula toward a retracted position to expose the distal end and the at least one anchor of the localization wire to the tissue mass, without inducing movement of the localization wire, and with the cannula being removable from the localization wire in its entirety.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.10/707,043, filed Nov. 17, 2003, which claims the benefit of U.S.provisional application Ser. No. 60/427,020, filed Nov. 18, 2002, andU.S. provisional application Ser. No. 60/427,024, filed Nov. 18, 2002,each of which is incorporated herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

In one aspect, the invention relates generally to an apparatus forimplanting a localization wire and more particularly to an apparatuscomprising a retractable cannula for implanting a preloaded localizationwire. In another aspect, the invention relates generally to a method forimplanting a localization wire and more particularly to a method forimplanting a preloaded localization wire by retracting a cannularelative to the localization wire.

2. Description of the Related Art

Localization wires are common devices for marking nonpalpable lesions ina tissue mass, usually breast tissue. When such a lesion is identifiedwith a medical imaging technique, such as radiography andultrasonography, it is often desirable to position a localization wireor other type of marker near the lesion to facilitate locating thelesion during later procedures, such as biopsy. Alternatively, alocalization wire can be placed in the tissue mass after a biopsy hasbeen taken. In this case, the localization wire marks the location ofthe biopsy cavity for future procedures, such as removal of thesurrounding tissue or therapeutic treatment. It is critical that thelocalization wire is accurately implanted in the correct location.Localization wires, which typically comprise an anchor portion and awire portion that extends from the anchor and through the skin surface,are especially effective for identifying lesions or biopsy sites becausea practitioner can use the wire as a physical guide to the lesion ratherthan solely relying on imaging techniques. For the surgical excision ofthe lesion, the localization wire is the preferred way for the surgeonto locate the lesion.

To implant a localization wire, a needle is inserted into the tissuemass and, with guidance from imaging systems, the needle is positionedwith its tip near a predetermined location. Once the needle is in place,the localization wire is manually threaded through the needle andinserted into the predetermined location. Thereafter, the needle isremoved from the tissue mass, and the localization wire remains in placeat the predetermined location. Alternatively, the needle is positionedwith its tip at the predetermined location, the localization wire ismanually advanced to the end of the needle, and the needle is manuallywithdrawn from the tissue mass. During either process, the wire can beinadvertently displaced from the predetermined location as the needle isremoved. As a result, the localization wire can be positioned deeper orshallower than intended and, therefore, can inaccurately mark thepredetermined location. Further, if ultrasonography is utilized forimaging, the procedure requires three hands: one to position the needle,a second to hold the ultrasonography transducer, and a third to feed thelocalization wire into the needle and tissue mass. If the three handsare not properly coordinated, then it can be difficult for thepractitioner to accurately position the localization wire.

Devices containing preloaded wires have been developed to eliminate theneed to thread the needle with the wire when the needle is inserted intothe tissue mass. The localization wires of such devices can be implantedinto the predetermined location by manual distal displacement of thelocalization wire. The practitioner can grasp the wire portion thatextends from the proximal end of the needle and push the localizationwire distally to insert the anchor portion into the tissue mass;however, this process still requires three hands. Alternatively, thedevice can comprise a plunger in operative communication with thelocalization wire. Displacement of the plunger into the needle forcesthe distal end of the localization wire past the tip of the needle andinto the predetermined location. The force applied to the plunger canaffect the final location of the localization wire. In order tocorrectly position the anchor, the practitioner must accurately placethe tip of the needle a sufficient distance from the predeterminedlocation and apply a suitable force to the plunger to displace thelocalization wire into the predetermined location.

There remains a desire amongst medical practitioners for a device thatcan accurately implant a localization wire and requires only a singlehand, thus freeing the other hand to hold the imaging device. Such adevice would make it possible for a single person to accurately placethe localization wire.

SUMMARY OF THE INVENTION

The invention, in one form thereof, is directed to an apparatus forpercutaneously implanting a localization wire within a tissue mass. Theapparatus includes a handle, and a cannula mounted to the handle. Thecannula defines a lumen and has a distal end forming an insertion tip.The cannula is movable relative to the handle between an insertionposition and a retracted position. A localization wire is positioned toextend from the handle and into the lumen of the cannula. Thelocalization wire has a distal end that is positioned near the insertiontip and is contained within the lumen when the cannula is in theinsertion position. The localization wire includes at least one anchoradapted to hold the localization wire in the tissue mass. The cannulaand the localization wire are configured such that each of the at leastone anchor remains completely contained in the cannula when the cannulais in the insertion position prior to the cannula being moved to theretracted position. An actuator is in operable communication with thecannula. The actuator is configured for operation between a chargedcondition and a discharged condition to retract the cannula toward theretracted position to expose the distal end of the localization wire tothe tissue mass and expose each of the at least one anchor to the tissuemass, without inducing movement of the localization wire, and with thecannula being removable from the localization wire in its entirety.

The invention, in another form thereof, is directed to an apparatus forpercutaneously implanting a localization wire within a tissue mass. Theapparatus includes a handle with a hollow interior and an end. A cannuladefines a lumen and has a distal insertion tip. The cannula is movablerelative to the handle between an insertion position and a retractedposition. A localization wire is located within the lumen and has adistal end near the distal insertion tip when the cannula is in theinsertion position. The localization wire includes at least one anchoradapted to hold the localization wire in the tissue mass. The cannulaand the localization wire are configured such that each of the at leastone anchor remains completely contained in the cannula when the cannulais in the insertion position prior to the cannula being moved to theretracted position. An actuator is operable between a charged conditionand a discharged condition to effect retraction of the cannula relativeto the localization wire. The handle, the cannula, the localizationwire, and the actuator form a self-contained implanting apparatusconfigured for implanting the localization wire into the tissue mass,whereby the cannula is inserted into the tissue mass and the actuator isplaced in the discharged condition to effect retraction of the cannularelative to localization wire to expose the distal end of thelocalization wire to the tissue mass and expose each of the at least oneanchor to the tissue mass, without inducing movement of the localizationwire, and with the cannula being removable from the localization wire inits entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of an apparatus for implanting a preloadedlocalization wire according to the invention, wherein the apparatus isshown in an uncocked condition.

FIG. 2 is a perspective view identical to FIG. 1, wherein a grip portionis illustrated in phantom to show a spring-loaded cannula disposedinside the grip portion;

FIG. 3 is a sectional view of the apparatus in FIG. 1.

FIG. 4 is an exploded view of the apparatus in FIG. 1.

FIG. 5 is an enlarged perspective view of a key and a keyway of theapparatus in FIG. 1.

FIG. 6 is an enlarged sectional view of the cannula and the key of theapparatus in FIG. 1 and showing the preloaded localization wire disposedtherein.

FIG. 7 is perspective view of the apparatus in FIG. 1 inserted into apredetermined location in a tissue mass, wherein the apparatus is in acocked condition and the cannula is in an insertion position.

FIG. 7A is a front plan view of the key and keyway of the apparatus inFIG. 7, wherein the key and keyway are unaligned.

FIG. 8 is a perspective view of the apparatus in FIG. 1, wherein thecannula is in an implant position to expose the localization wire to thepredetermined location of the tissue mass.

FIG. 8A is a front plan view of the key and keyway of the apparatus inFIG. 8, wherein the key and keyway are aligned.

FIG. 9 is a plan view of the localization wire in FIG. 8 implanted inthe tissue mass, wherein the apparatus has been removed from thelocalization wire.

FIG. 10 is a perspective view of a second embodiment of an apparatus forimplanting a preloaded localization wire according to the invention,with the apparatus shown in a cocked condition.

FIG. 11 is an exploded view of the apparatus in FIG. 10.

FIG. 12 is a perspective view identical to FIG. 10, wherein a handle isillustrated in phantom to show a spring-loaded cannula disposed insidethe handle and the cannula is in an insertion position.

FIG. 12A is a front plan view of a key and a keyway of the apparatus inFIG. 9, wherein the key and keyway are unaligned.

FIG. 13 is a perspective view of the apparatus in FIG. 10, wherein thecannula is in an implant position to expose the localization wire.

FIG. 13A is a front plan view of the key and the keyway of the apparatusin FIG. 13, wherein the key and keyway are aligned.

FIG. 14 is a perspective view of a third embodiment of an apparatus forimplanting a preloaded localization wire according to the invention,with the apparatus shown in a cocked condition.

FIG. 15 is an exploded view of the apparatus in FIG. 14.

FIG. 15A is a front plan view of a trigger with a keyway from theapparatus in FIG. 15.

FIG. 16 is perspective view identical to FIG. 14, wherein a handle isillustrated in phantom to show a spring-loaded cannula disposed insidethe handle and the cannula is in an insertion position.

FIG. 16A is a front plan view of a key and the trigger of the apparatusin FIG. 16, wherein the key and keyway are unaligned.

FIG. 17 is a perspective view of the apparatus in FIG. 14, wherein thecannula is in an implant position to expose the localization wire.

FIG. 17A is a front plan view of the key and the trigger of theapparatus in FIG. 17, wherein the key and keyway are aligned.

FIG. 18 is a plan view of a fourth embodiment of an apparatus forimplanting a preloaded localization wire according to the invention,with the apparatus shown in a cocked condition.

FIG. 19 is a sectional view of the apparatus in FIG. 18, wherein thecannula is in an insertion position.

FIG. 20 is a sectional view of the apparatus in FIG. 18, wherein thecannula is in an implant position to expose the localization wire.

FIG. 21 is an enlarged view of the end of the localization wire of FIG.20.

FIG. 22 is a side view of an alternative localization wire with radiallyoffset opposing barbs.

FIG. 23 is a front view of the alternative localization wire of FIG. 24.

FIG. 24 is a perspective view of a fifth embodiment of an apparatus forimplanting a preloaded localization wire according to the invention,with the apparatus shown in the cocked position and a cannula in theinsertion position.

FIG. 25 is a perspective view similar to FIG. 24 except that theapparatus is shown in the uncocked position and the cannula in theimplant position.

FIG. 26 is a longitudinal sectional view of the apparatus of FIG. 25.

DESCRIPTION OF THE INVENTION

The invention provides an apparatus for accurately implanting alocalization wire within a tissue mass. The apparatus comprises apreloaded localization wire and a cannula that retracts proximally toexpose the localization wire. Implantation of a localization wire withthe apparatus requires only one hand.

Referring now to the figures, FIGS. 1-9 illustrate a first embodiment ofa implanting apparatus 10 according to the invention, which is capableof the percutaneous placement of a localization wire at a predeterminedlocation, such as a lesion or a biopsy site, within a tissue mass 150.The implanting apparatus 10 comprises a handle 20 for housing a cannula60, a localization wire 80 partially contained within the cannula 60,and an actuator 90 for displacing the cannula 60 relative to thelocalization wire 80. It will become apparent in the followingdescription that the handle 20, the cannula 60, the localization wire80, and the actuator 90 form a self-contained implanting apparatus 10.

The handle 20 includes a grip portion 22 slidably mounted to a baseportion 24 with a hollow interior 26, a closed proximal end 28, and anopen distal end 30. The base portion 24 further comprises diametricallyopposed L-shaped grooves 36 adjacent the hollow interior 26. Each groove36, best viewed in FIG. 5, has a circumferential recess 34 that formsone leg of the L at the distal end 30 and a longitudinal keyway 32 thatextends from an end of the circumferential recess 34 towards theproximal end 28 to form the other leg of the L. A pair of diametricallyopposed resilient tabs 38 is located on the outside surface of the baseportion 24 near the distal end 30.

The grip portion 22 defines a hollow interior 40 (FIG. 3) and comprisesa distal end 42 with a wall 43 having an aperture 41 for slidablymounting the cannula 60 and an open proximal end 44 that receives thedistal end 30 of the base portion 24. Further, the grip portion 22includes first and second pairs 46 and 48 of diametrically opposedopenings sized to receive the tabs 38. The first pair 46 of openings islocated near the proximal end 44, and the second pair 48 are spaced fromthe first pair 46 at a distance less than the length of the base portion24. A transverse slot 50 formed between first and second trigger armstops 52 and 54 extends through the grip portion 22 near the distal end48. The transverse slot 50 has an arc length substantially equal to thatof the circumferential recess 34 of the groove 36.

The handle 20 is slidable between an uncocked condition, as illustratedin FIGS. 1-3, and a cocked condition, as shown in FIG. 7. In theuncocked condition, the first pair 46 of openings receives the tabs 38,and the proximal end 44 of the grip portion 22 is near the distal end 30of the base portion 24. In the cocked condition, the second pair 48 ofopenings receives the tabs 38, and the proximal end 44 of the gripportion 22 is near the proximal end 28 of the base portion 24. Theinteraction of the tabs 38 with the first and second pairs 46 and 48 ofopenings secures the handle 20 in the uncocked and cocked conditions,respectively. When the grip portion 22 slides from the uncockedcondition to the cocked condition, distal displacement of the first pair46 of openings deflects the resilient tabs 38 towards the base portion24 such that the grip portion 22 can slide over the tabs 38 until thesecond pair 48 of openings aligns with and receives the tabs 38.

Referring now to FIGS. 4 and 6, the cannula 60 defines a lumen 62 andcomprises a proximal end 64 mounted to a key 66 and a distal end 68 thatforms an insertion tip 65. The key 66 includes a collar 67 withdiametrically opposed key projections 70 and a sheath 72 that extendsdistally from the collar 67 to encase the proximal end 64 of the cannula60. The distal end 68 of the cannula 60 can be sharpened to facilitateinsertion into the tissue mass 150 (FIG. 7). Further, cannula 60comprises an imageable portion 74, preferably at least at the distal end68, for enhanced visibility using common imaging techniques, such asradiography, ultrasonography, and magnetic resonance imaging (MRI).Multiple imageable portions 74 can be spaced along the cannula 60 atpredetermined intervals and effectively utilized as a ruler whendisposed within the tissue mass 150. Suitable cannula tips are disclosedin U.S. Pat. No. 5,490,521, issued Feb. 13, 1996 to R. E. Davis and G.L. McLellan, which is incorporated by reference. Ultrasound enhancementtechnology is also disclosed in U.S. Pat. No. 4,401,124, issued Aug. 30,1983 to J. F. Guess et al.; and U.S. Pat. No. 4,582,061, issued Apr. 15,1986 to F. J. Fry.

With particular reference to FIGS. 4, 6 and 9, the localization wire 80comprises a distal end 82 near which is located at least one anchor 84for securing the localization wire 80 in the tissue mass 150. The anchor84 in this embodiment is an integrally formed, single barb; however, theanchor 84 can be in the form of a hook, a loop, a coil, a pair ofopposing barbs, or any other suitable form. Similar to the cannula 60,the localization wire 80 can comprise an imageable portion 86, at thedistal end 82 or along the entire length of the wire 80, for enhancedvisibility using common imaging techniques, such as radiography,ultrasonography, and magnetic resonance imaging (MRI). For example, thesurface contour of the localization wire 80 can change at certainlocations or at periodic intervals, such that those locations appeardifferent from the rest of the wire 80 when using an imaging technique.The change in contour can be achieved by etching to remove material fromthe surface. Another example of an imageable portion 86 is incorporationof beads or loops into the wire 80 at the distal end 82 or along theentire length of the wire 80 to provide a palpable reference.

The cannula 60 is movable between an insertion position, as illustratedin FIGS. 1-3 and 7, and an implant position, as depicted in FIG. 8. Inthe insertion position, the cannula 60 extends distally from the handle20 to facilitate insertion into the tissue mass 150, and the anchor 84is preferably completely contained within the cannula 60. In thisembodiment, the key 66 abuts the distal end 30 of the handle baseportion 24, and the key projections 70 are seated in the circumferentialrecesses 34 of the grooves 36 but are spaced from the respectivelongitudinal keyways 32. The configuration of the key 66 relative to thegrooves 36 when the cannula 60 is in the insertion position is bestviewed in FIG. 7A. In the implant position, the cannula is proximallyretracted into the hollow interior 26 of the handle 20, and the anchor84 is located exteriorly of the cannula 60 and exposed to the tissuemass 150. In this embodiment, the key projections 70 are rotatedrelative to the insertion position such that they are aligned with therespective longitudinal keyways 32 to enable displacement of the key 66and, therefore, the cannula 60 into the handle grip portion 24. Theposition of the key projections 70 relative to the grooves 36 when thecannula 60 is in the implant position is best seen in FIG. 8A.

The localization wire 80 and the cannula 60 are sized such that they areindependently moveable. In other words, movement of the cannula 60 doesnot induce movement of the localization wire 80, and the localizationwire 80 is free to move within and relative to the cannula 60. As aresult, the localization wire 80 is stationary during retraction of thecannula 60, and inadvertent displacement of the localization wire 80 isavoided.

To ensure that the localization wire 80 does not move in response to themovement of the cannula 60, the localization wire 80 can have a portionthat is fixed relative to the handle or some other structure that doesnot move with the cannula 60.

When the cannula 60 is in the insertion position, the localization wire80 is preloaded within the lumen 62 and extends into the hollow interior26 of the handle base portion 24, as seen in FIG. 3. In particular, thedistal end 82 of the localization wire 80 is positioned near theinsertion tip 65 such that the cannula 60 sheaths the anchor 84, asshown in FIG. 6. If necessary, the anchor 84 can be compressed to fitwithin the lumen 62. When the cannula 60 retracts to the implantposition, the localization wire 80 is stationary; therefore, the distalend 82 and anchor 84 of the localization wire 80 become exposed to theirsurroundings, as illustrated in FIG. 8. Because the anchor 84 of thelocalization wire 80 is disposed near the cannula insertion tip 65 andis not displaced during retraction of the cannula 60, the practitioneronly has to position the insertion tip 65 when the cannula 60 isinserted into tissue mass 150.

The actuator 90 for automatically moving the cannula 60 from theinsertion position to the implant position comprises a biasing element,which is shown as a spring 94 with a proximal end 93 and distal end 95,and a trigger 92 in operable communication with the key 66. The trigger92 includes a hollow finger 96, which has open proximal and distal ends98 and 100, rotatably disposed in the grip portion 22. Diametricallyopposed longitudinal grooves 104 sized to receive the diametricallyopposed key projections 70 extend from the proximal end 98 of the finger96. The spring 94 extends through the hollow finger 96, with theproximal and distal ends 93 and 95 of the spring 94 abutting the keycollar 67 and the wall 43 of the grip portion 22, respectively.

The trigger 92 further comprises a trigger arm 106 that extends radiallyfrom the finger 96 and through the transverse slot 50 in the gripportion 22. Movement of the trigger arm 106 within the transverse slot50 rotates the trigger 92 between a ready position and a releaseposition. When the trigger arm 106 is adjacent the first trigger armstop 52 (FIG. 7), the trigger 92 is in the ready position. Movement ofthe trigger arm 106 to the second trigger arm stop 54 (FIG. 8) placesthe trigger 92 in the release position.

The actuator 90 is operable between a charged condition and a dischargedcondition. When the actuator 90 is in the charged condition, as in FIG.7, the trigger 92 is in the ready position, and the spring 94 is in acompressed state. Additionally, the finger grooves 104 engage the keyprojections 70, which are unaligned with the respective longitudinalkeyways 32. When the actuator 90 is in the discharged condition, as inFIG. 8, the trigger 92 is in the release position, and the spring 94 isin an expanded state. To move the actuator 90 from the charged conditionto the discharged condition, the trigger arm 106 is circumferentiallydisplaced along the transverse slot 50 to effect rotation of the finger96 and to move the trigger 92 to the release position. Because thefinger grooves 104 are engaged with the key projections 70, the key 66rotates with the finger 96 until the key projections 70 align with thelongitudinal keyways 32. Once the key projections 70 and thelongitudinal keyways 32 are aligned, the spring 94 expands from thecompressed state and pushes the cannula 60 to the implant position. InFIG. 8, the spring 94 is not shown in order to provide a clearillustration of the interior of the implanting apparatus 10.

Referring again to FIG. 2, in operation, the apparatus 10 begins withthe handle 20 in the uncocked condition and the cannula 60 in theinsertion position. In this position, the cannula 60 and localizationwire 80 are protected by the handle 20 from being bent or damaged duringhandling prior to implanting the localization wire 80. Even though thetrigger 92 is in the ready position, the spring 94 in the expandedstate, and the finger grooves 104 are not engaged with the keyprojections 70; therefore, the actuator 90 is not yet in the chargedcondition. Consequently, accidental discharge of the actuator 90 whenthe apparatus 10 is in the uncocked condition is not possible.

To move the handle 20 to the cocked condition in FIG. 7, a practitionersituates the proximal end 28 of the body portion 24 against a surfaceand applies a proximal force to the grip portion to slide the gripportion 22 over the body portion 24. Alternatively, the body portion 24can be pushed distally into the grip portion 22. Movement of the handle20 from the uncocked condition to the cocked condition exposes thecannula 60 and sets the actuator 90 in the charged condition. Inparticular, movement of the grip portion 22 displaces the actuatorfinger 96 towards the body portion 24 and transforms the spring 94 fromthe expanded state to the compressed state. As the finger 96 approachesthe key 66, the finger grooves 104 engage the key projections 70. Thecannula 60 with the localization wire 80 therein remains in theinsertion position.

With the apparatus 10 in the condition shown in FIG. 7, the cannula 60is inserted into the tissue mass 150 so that its insertion tip 65 is atthe predetermined location, which is illustrated as a lesion 160 inFIGS. 7 and 8. Preferably, the cannula 60 with the localization wire 80contained therein is positioned within the tissue mass 150 by using theimageable portions 74 in conjunction with a suitable imaging system. Asstated above, only the cannula insertion tip 65 requires positioningwhen the cannula 60 is inserted into the tissue mass 150. The design ofthe apparatus 10 enables the practitioner to use one hand to move thehandle 20 to the cocked condition and insert the cannula 60 into thetissue mass 150; the other hand can hold an ultrasonic transducer to aidin positioning the cannula 60 and the localization wire 80.

Referring now to FIG. 8, to implant the localization wire 80, thepractitioner, preferably using the same hand as above for cocking andinserting the apparatus 10, moves the actuator 90 to the dischargedcondition by rotating the trigger arm 106 from the first trigger armstop 52 to the second trigger arm stop 54 to move the trigger 92 fromthe ready position to the release position. As discussed earlier,rotation of the trigger arm 106 induces rotation of the finger 96 andthe key 66. Upon sufficient rotation of the key 66, the key projections70 align with the longitudinal keyways 32, thereby enabling proximaldisplacement of the cannula 60. Once alignment is achieved, the spring94 simultaneously expands from the compressed state and forces thecannula 60 to the implant position. The cannula 60 retracts relative tothe stationary localization wire 80 and into the handle 20. Preferably,the retracted cannula 60, including the insertion tip 65, is containedentirely within the handle 20 for safety purposes. Retraction of thecannula 60 exposes the distal end 82 of the localization wire 80 to thetissue mass 150, and the anchor 84 deploys at the predetermined locationto embed the localization wire 80 in the tissue mass 150.Advantageously, the localization wire 80 does not move during theimplant process, and, consequently, the anchor 84 is embedded where thepractitioner positions it during insertion, which greatly improves theplacement accuracy over the prior art. After the anchor 84 is implantedat the predetermined location, the apparatus 10 is removed from thelocalization wire 80, which remains in the tissue mass 150, as depictedin FIG. 9.

A second embodiment of an implanting apparatus 10′ according to theinvention is illustrated in FIGS. 10-13A where similar components areidentified with the same reference numeral bearing a prime (′) symbol.The second embodiment is very similar to the first embodiment; theprimary difference is the handle 20′ of the second embodiment. The firstembodiment handle 20 comprises the grip portion 22 and the body portion24, which are initially in an uncocked condition. Conversely, the secondembodiment handle 20′ is a single element having a cap 200 at itsproximal end 28′ and a distal wall 43′ with an aperture 41′ for slidablyreceiving the cannula 60′. The handle 20′ does not have a similaruncocked condition; rather, the second embodiment is assembled andshipped in the cocked condition, with the cannula being exposed to thesurrounding environment.

Referring to FIGS. 11-13A, instead of grooves 36 on the inside surfaceof the handle 20, the second embodiment handle 20′ comprises a keywaydisk 202 disposed adjacent to the proximal end 98′ of the trigger finger96′. The keyway disk 202 includes a keyway 32′ having a shapecorresponding to that of the key collar 67′ and the key projections 70′.In the illustrated embodiment, the keyway 32′ comprises a circularportion 206 and diametrically opposed rectangular portions 208. When thecannula 60′ is in the insertion position in FIG. 12, the anchor 84′ ofthe localization wire 80′ is retained within the cannula 60′, and thekey 66′ abuts the distal side of the keyway disk 202 and is orientedsuch that the key projections 70′ are not aligned with the rectangularportions 208. This configuration, best viewed in FIG. 12A, preventsmovement of the cannula 60′ through the keyway 32′. When the cannula 60′is in the implant position shown in FIG. 13, the key projections 70′ arerotated relative to the insertion position such that they are alignedwith rectangular portions 208 of the keyway 32′ to enable displacementof the key 66′ and, therefore, the cannula 60′ into the hollow interior26′ of the handle 20′, and the anchor 84′ of the localization wire 80′is exterior of the cannula 60′ and exposed to the surrounding tissue. InFIG. 13, the spring 94′ is not shown in order to provide a clearillustration the interior of the apparatus 10′. The position of the keyprojections 70′ relative to the keyway 32′ when the cannula 60′ is inthe implant position is best seen in FIG. 13A.

The operation of the second embodiment is substantially the same as, ifnot identical to, the operation of the first embodiment, excluding thecocking step. Because the second embodiment apparatus 10′ is initiallyin a cocked condition, the operation begins with the step of insertingthe cannula 60′ into the tissue mass 150′. Once the cannula 60′ and thelocalization wire 80′ are at the predetermined location, thepractitioner rotates the trigger arm 106′ within the transverse slot 50′to move the trigger 92′ from the ready position to the release positionand thereby align the key projections 70′ with the longitudinal keyways32′. Upon alignment, the spring 94′ expands and forces the cannula 60′to the implant position to expose the distal end 82′ of the localizationwire 80′ to the tissue mass 150′. After the anchor 84′ is secured in thetissue mass 150′, the apparatus 10′ is removed from the localizationwire 80′.

A third embodiment of an implanting apparatus 10″ according to theinvention is illustrated in FIGS. 14-17A where similar components areidentified with the same reference numeral bearing a double prime (″)symbol. The primary difference between the second and third embodimentsis the actuator trigger 92″. The third embodiment trigger 92″, which isbest seen in FIG. 15A, comprises a keyway 32″ corresponding to the shapeof the key 66″, a recess 34″ offset from the keyway 32″, and a surface302 designed to support a finger of the practitioner. The trigger 92″ ismounted to a transverse slot 304 in the handle 20″ and is slidablymovable between the ready and release positions. The trigger 92″ of thethird embodiment effectively replaces the keyway disk 202 of the secondembodiment.

When the cannula 60″ is in the insertion position shown in FIG. 16, thekey collar 67″ abuts the distal side of the trigger 92″ and resides inthe recess 34″ such that the collar 67″ is unaligned with the keyway32″. This configuration, best viewed in FIG. 16A, corresponds to theready position of the trigger 92″. In the ready position, the trigger92″ prevents retraction of the cannula 60″ relative to the localizationwire 80″. To move the cannula 60″ to the implant position shown in FIG.17, the trigger 92″ slides to the release position, wherein the keyway32″ aligns with the key collar 67″ to enable displacement of the key 66″and, therefore, the cannula 60″ into the hollow interior 26″ of thehandle 20″. In FIG. 17, the spring 94″ is not shown in order to providea clear illustration the interior of the apparatus 10″. The position ofthe key projections 70″ relative to the keyway 32″ when the trigger 92″is in the release position is best seen in FIG. 17A.

The operation of the third embodiment is substantially the same as theoperation of the second embodiment; the primary difference is theoperation of the actuator 90″, particularly the trigger 92″. Rather thanrotating the trigger arm 106′ through the transverse slot 50′, thetrigger 92″ is actuated by pushing on the surface 302 to slide thetrigger 92″ through the transverse slot 304 from the ready position tothe release position.

A fourth embodiment of a implanting apparatus 10′″ according to theinvention is illustrated in FIGS. 18-20, where similar components areidentified with the same reference numeral bearing a triple prime (′″)symbol. The fourth embodiment is substantially the same as the secondand third embodiments, with the fourth embodiment illustrating analternative actuator trigger 92′″. The trigger 92′″ includes a surface400 designed to support a finger of the practitioner and comprises apivot arm 402 that terminates in a finger 404. The trigger 92′″ ismounted to the handle 20′″ at a pivot pin 406 and is pivotable betweenready and release positions.

When the trigger 92′″ is in the ready position shown in FIG. 19, thefinger 404 abuts the proximal side of the collar 67′″ to support thecannula 60′″ against the bias of the spring 94′″ and retain the cannula60′″ in the insertion position. To move the trigger 92′″ to the releaseposition, downward force applied to the surface 400 pivots the trigger92′″ about the pivot pin 406 to remove the finger 404 from abuttingcontact with the collar 67′″. As a result, the biasing force of thespring 94′″ moves the cannula 60′″ to the implant position.

The operation of the fourth embodiment is substantially the same as theoperation of the second and third embodiments; the primary difference isthe operation of the actuator 90′″, particularly the actuation trigger92′″. To discharge the actuator 90′″, the practitioner simply applies adownward force to the surface 400 of the trigger 92′″.

In the descriptions of various embodiments of the implanting apparatus10, the localization wire 80 has been shown as being completely disposedwithin the cannula 60 and the handle 20. However, it is within the scopeof the invention for the localization wire 80 to extend through andbeyond the proximal end 28 of the handle base portion 24. Such aconfiguration would facilitate implantation of a longer localizationwire 80 with the same size apparatus 10.

To avoid accidental injury prior to insertion of the cannula 60 into thetissue mass 150, the apparatus 10 can optionally include a removablesheath or removable safety cap that encases the exposed portion of thecannula 60 or at least the insertion tip 65 of the cannula 60.

Referring to FIGS. 20 and 21, the localization wire 80′″ has some uniquefeatures compared to a traditional localization wire. The localizationwire 80′″ comprises opposing anchors formed by opposing sets of barbs84′″ that extend from the shaft of the localization wire. The opposingsets of barbs 84′″ resist the movement of the localization wire ineither direction along the longitudinal axis of the shaft.

Preferably, and as illustrated, the opposing barbs are angled inopposite directions relative to the shaft. That is, each barb forms anacute interior angle relative to the shaft, but the acute interior anglefaces towards an opposite end of the shaft. The opposing barb structureis ideal for use in less dense or structurally strong tissue, such asfatty tissue.

FIGS. 22 and 23 illustrates another localization wire 80″″ incorporatingthe opposing barbs 84″″, which in this case are radially offset to eachother and are not arranged in sets as in the localization wire 80′″.

The opposing barbs can be arranged in a variety of different ways. Theycan be arranged in cooperative sets, individual barbs or a combinationof both. There can be an equal or unequal number of opposing barbs. Thebarbs can be radially aligned or unaligned.

The barbs can also be formed in a variety of ways. For example, thebarbs can be integrally formed with the shaft of the localization wire,such as in bending a portion of the shaft. Alternatively, the barbs canbe separate pieces affixed to the shaft, such as by laser weldingseparate wire elements to the shaft.

FIGS. 24-26 illustrate a fifth embodiment apparatus 510 for implanting alocalization wire. The fifth embodiment 510 comprises a handle 520, witha hollow interior 526. A passageway 527 extends from the hollow interior526 to the nose or distal end of the handle 520. A longitudinal slot 529is formed in the upper surface of the handle 520 and extends to thehollow interior 526.

A cannula 560 is slidably received within the passageway 527 and canreciprocate relative to the handle. A trigger 592 in the form of a slideis received within the slot 529 and is slidably moveable between theopposing ends of the slot. A proximal end of the cannula 560 is mountedto the trigger, such that the sliding movement of the trigger in theslot 529 effects the sliding movement of the cannula 560 relative to thehandle 520.

A localization wire 580 is preloaded into the cannula. The sliding ofthe cannula into the handle results in the exposing of the localizationwire to the environment previously surrounding the cannula.

In operation, the apparatus 510 is grasped by the user in the conditionas illustrated in FIG. 24. In this condition, the apparatus is cockedand the cannula is in the insertion position. The user then inserts thecannula into the tissue mass, directly or through a positioning cannula,and locates the cannula as desired. The user then slides the trigger 592to the release position as illustrated in FIG. 25, which causes thecannula to retract relative to the localization wire and expose thelocalization wire to the surrounding tissue. The user can then pull onthe handle to withdraw the cannula from the tissue, leaving thelocalization wire.

The main difference between the fifth embodiment and the priorembodiments is that the cannula is manually moved from the insertposition to the implant position. The prior embodiments automatically,not manually, moved the cannula. While the manual movement of the fifthembodiment is a more simple implementation, it is not preferred over theautomatic implanting. It is believed that the automatic implanting ismore accurate in that the user will be less like to move the apparatusrelative to the tissue mass, thereby increasing the accuracy of theplacement of the localization wire.

The inventive apparatus for percutaneously implanting a localizationwire offers several advantages. Because the process of implanting thelocalization wire involves retracting the cannula without axialdisplacement of the localization wire, the practitioner can position thelocalization wire, which only requires positioning the insertion tip ofthe cannula, at the desired implantation location during insertion ofthe apparatus into the tissue mass. This feature facilitates accurateplacement of the localization wire within the tissue mass, which iscritical to pinpointing the predetermined location during futureprocedures. Retraction of the entire cannula, including the insertiontip, into to the handle prevents accidental injury during removal of thedevice. Additionally, the actuator of the inventive apparatus retractsthe cannula automatically, thereby ensuring that a suitable force isapplied to the cannula and reducing the possibility of human error.Because the inventive apparatus has a preloaded localization wire andcan be operated with a single hand, the practitioner can utilize theother hand to control an imaging system and does not require theassistance of a third hand. Furthermore, the first embodiment of theapparatus is provided in an uncocked condition wherein the spring is inan expanded state, which not only prevents accidental discharge but alsoincreases the shelf life of the spring and, therefore, the apparatus.

While the invention has been specifically described in connection withcertain specific embodiments thereof, it is to be understood that thisis by way of illustration and not of limitation, and the scope of theappended claims should be construed as broadly as the prior art willpermit.

1-20. (canceled)
 21. An apparatus for implanting a localization wirewherein the apparatus exhibits a ready configuration and a relaxedconfiguration, and comprises: a handle having a slot; a cannula disposedwithin the handle and having an insertion tip and a projectionconfigured to selectively enter the slot, wherein the cannula is movablebetween a ready configuration and a relaxed configuration; alocalization wire disposed within the cannula; and an actuatorconfigured to retract the cannula into the handle.
 22. The apparatus ofclaim 21, wherein the apparatus is self-contained.
 23. The apparatus ofclaim 22, comprising a biasing element operatively connected to theactuator.
 24. The apparatus of claim 23, wherein the localization wirehas an anchor.
 25. The apparatus of claim 24, wherein the localizationwire has two or more radially offset opposing anchors.
 26. The apparatusof claim 25, wherein the localization wire is imageable.
 27. Theapparatus of claim 26, wherein the ready configuration comprises acompressed biasing element and the relaxed configuration comprises anexpanded biasing element.
 28. The apparatus of claim 21, comprising abiasing element operatively connected to the actuator.
 29. The apparatusof claim 28, wherein the localization wire has an anchor.
 30. Theapparatus of claim 29, wherein the localization wire has two or moreradially offset opposing anchors.
 31. The apparatus of claim 30, whereinthe localization wire is imageable.
 32. The apparatus of claim 31,wherein the ready configuration comprises a compressed biasing elementand the relaxed configuration comprises an expanded biasing element. 33.The apparatus of claim 32, wherein the localization wire has two or moreradially offset opposing anchors.
 34. The apparatus of claim 21, whereinthe ready configuration comprises a compressed biasing element and therelaxed configuration comprises an expanded biasing element.
 35. Theapparatus of claim 34, wherein the localization wire has an anchor. 36.The apparatus of claim 21, wherein the localization wire has an anchor.37. The apparatus of claim 36, wherein the localization wire has two ormore radially offset opposing anchors.
 38. The apparatus of claim 37,wherein the localization wire is imageable.
 39. The apparatus of claim38, wherein the ready configuration comprises a compressed biasingelement and the relaxed configuration comprises an expanded biasingelement.
 40. A self-contained apparatus for implanting a localizationwire wherein the apparatus exhibits a ready configuration and a relaxedconfiguration, and comprises: a handle having a slot; a cannula disposedwithin the handle and having an insertion tip and a projectionconfigured to selectively enter the slot, wherein the cannula is movablebetween a ready configuration and a relaxed configuration; an imageablelocalization wire disposed within the cannula and having two or moreradially offset opposing anchors; an actuator configured to retract thecannula into the handle; and a biasing element operatively connected tothe actuator, wherein the ready configuration comprises a compressedbiasing element and the relaxed configuration comprises an expandedbiasing element.